Datasheet

83
11011B–ATARM–21-Feb-12
SAM3N
10.11.4.4 ROR
Rotate right by n bits moves the left-hand 32-n bits of the register Rm, to the right by n places,
into the right-hand 32-n bits of the result. And it moves the right-hand n bits of the register into
the left-hand n bits of the result. See Figure 10-7.
When the instruction is RORS or when ROR #n is used in Operand2 with the instructions MOVS,
MVNS, ANDS, ORRS, ORNS, EORS, BICS, TEQ or TST, the carry flag is updated to the last bit
rotation, bit[n-1], of the register Rm.
•If n is 32, then the value of the result is same as the value in Rm, and if the carry flag is
updated, it is updated to bit[31] of Rm.
• ROR with shift length, n, more than 32 is the same as ROR with shift length n-32.
Figure 10-7. ROR #3
10.11.4.5 RRX
Rotate right with extend moves the bits of the register Rm to the right by one bit. And it copies
the carry flag into bit[31] of the result. See Figure 10-8 on page 83.
When the instruction is RRXS or when RRX is used in Operand2 with the instructions MOVS,
MVNS, ANDS, ORRS, ORNS, EORS, BICS, TEQ or TST, the carry flag is updated to bit[0] of
the register Rm.
Figure 10-8. RRX
10.11.5 Address alignment
An aligned access is an operation where a word-aligned address is used for a word, dual word,
or multiple word access, or where a halfword-aligned address is used for a halfword access.
Byte accesses are always aligned.
The Cortex-M3 processor supports unaligned access only for the following instructions:
• LDR, LDRT
• LDRH, LDRHT
• LDRSH, LDRSHT
•STR, STRT
• STRH, STRHT
31 10
Carry
Flag
...
2345
31 30
1
0
Carry
Flag
... ...